1. Field of the Invention
The present invention is related to a liquid crystal display panel and an active matrix substrate, and more particularly to a liquid crystal display panel with wide viewing angle and an active matrix substrate thereof.
2. Description of Related Art
Nowadays, the functions that the market demands of the thin film transistor liquid crystal display (TFT-LCD) tend to be high contrast ratio, high luminance, quick response and wide viewing angle. Currently, the technologies that meet the requirement of wide viewing angle include, for example, the twisted nematic (TN) LCD with a wide viewing film, the in-plane switching (IPS) LCD, the fringe field switching (FFS) LCD and the multi-domain vertical alignment (MVA) TFT-LCD.
In the conventional MVA-LCD panel, since alignment protrusions or slits formed on the color filter substrate or the TFT array substrate can render liquid crystal molecules arranged in multiple directions, thereby achieving multi-domain. Therefore, the MVA-LCD panel can meet the requirement of wide viewing angle.
Although the conventional MVA-LCD panel meets the requirement of wide viewing angle, it has the problem of color shift. The so-called color shift means users would see an image having gray scales different from the original image when viewing images on the display device from different viewing angles. For example, users would see an image lighter than the original image if viewing from a large angle. The problem of color shift would deteriorate the display quality of the image. Solutions have been proposed to solve this problem so far. One of the solutions is forming an additional capacitor in a single pixel unit. The capacitor makes the pixel electrodes in the single pixel unit generate electric fields of different intensities by electrical coupling, thereby generating different arrangements of liquid crystal molecules. Although the method can mitigate the phenomenon of color shift, it tends to result in the resistance-capacitance (RC) delay effect and thus causing distorted display images and poor display quality. Another method is adding one more transistor in a single pixel unit. In other words, a single pixel unit has two transistors. The two transistors make the pixel electrodes in the single pixel unit generate different electric fields and thus generating different arrangements of liquid crystal molecules so as to eliminate color shift. However, the method requires forming two transistors within a single pixel unit and adding lines (such as scan lines) so that the fabrication process is complicated and the fabrication cost is higher as well.